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Validations

1. Gateways

1.1. More than one Gateway for the same host port combination

Gateway creates a proxy that forwards the inbound traffic for the exposed ports. If two different gateways expose the same ports for the same host, this creates ambiguity inside Istio as either of these gateways could handle the traffic. This is most likely a configuration error. This check is done across all namespaces the user has access to.

Resolution

Remove the duplicate gateway entries or merge the two gateway definitions into a single one.

Severity

Warning

Example

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: bookinfo-gateway
  namespace: bookinfo
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: bookinfo-gateway-copy
  namespace: bookinfo2
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"
---

1.2. No matching workload found for gateway selector in this namespace

This validation checks the current namespace for matching workloads as this is recommended, and potentially in the future required, by the Istio. Excluded from this check are the default "istio-ingressgateway" and "istio-egressgateway" workloads which are included in Istio by default.

Although your traffic might be correctly routed to a workload in other namespace, this is not a guaranteed behavior and thus a warning is flagged in such cases also.

Resolution

Deploy the missing workload or fix the selector to target a correct location.

Severity

Warning

Example

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: bookinfo-gateway
  namespace: bookinfo
spec:
  selector:
    app: nonexisting # workload doesn't exist in the namespace
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "*"

2. Destination rules

2.1. More than one Destination Rule for the same host subset combination

Istio applies traffic rules for services after the routing has happened. These can include different settings such as connection pooling, circuit breakers, load balancing, and detection. Istio can define the same rules for all services under a host or different rules for different versions of the service.

This validation warning could be a result of duplicate definition of the same subsets as well as from rules that apply to all subsets. Also, a combination of one Destination Rule (DR) applying to all subsets and another defining behavior for only some subsets triggers this validation warning.

Istio silently ignores the duplicate subsets and merge these destination rules without letting the user know. Only the first seen rule (by Istio) per subset is used and information from multiple definitions is not merged. While the routing might work correctly, this is most likely a configuration error. It may lead to a undesired behavior if one of the offending rules is removed or modified and that is probably not the intention of the deployer of this service. Also, if the two offending destination rules have different policies for traffic routing the wrong one might be used.

Resolution

Either merge the settings to a single DR or split the subsets in such a way that they do not interleave. This ensures that the routing behavior stays consistent.

Severity

Warning

Example

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews-dr1
spec:
  host: reviews
  trafficPolicy:
    loadBalancer:
      simple: RANDOM
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews-dr2
spec:
  host: reviews
  trafficPolicy:
    loadBalancer:
      simple: RANDOM
  subsets:
  - name: v1
    labels:
      version: v1

2.2. This host has no matching entry in the service registry (service, workload or service entries)

Istio applies traffic rules for services after the routing has happened. These can include different settings such as connection pooling, circuit breakers, load balancing, and detection. Istio can define the same rules for all services under a host or different rules for different versions of the service. The host must a service that is defined in the platform’s service registry or as a ServiceEntry. Short names are extended to include '.namespace.cluster' using the namespace of the destination rule, not the service itself. FQDN is evaluated as is. It is recommended to use the FQDN to prevent any confusion.

If the host is not found, Istio ignores the defined rules.

Resolution

Correct the host to point to a correct service, in this namespace or with FQDN to other namespaces, or deploy the missing service to the mesh.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: notpresent
  trafficPolicy:
    loadBalancer:
      simple: RANDOM
  subsets:
  - name: v1
    labels:
      version: v1
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3

2.3. This subset’s labels are not found in any matching host

Istio applies traffic rules for services after the routing has happened. These can include different settings such as connection pooling, circuit breakers, load balancing, and detection. Istio can define the same rules for all services under a host or different rules for different versions of the service. The host must a service that is defined in the platform’s service registry or as a ServiceEntry. Short names are extended to include '.namespace.cluster' using the namespace of the destination rule, not the service itself. FQDN is evaluated as is. It is recommended to use the FQDN to prevent any confusion.

Subsets can override the global settings defined in the DR for a host.

If the host is not found, Istio ignores the defined rules.

Resolution

Correct the host to point to a correct service, in this namespace or with FQDN to other namespaces, or deploy the missing service to the mesh. If the hostname is equal to the one used otherwise in the DR, consider removing the duplicate host resolution.

Also, verify that the labels are correctly matching a workload with the intended service.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  trafficPolicy:
    loadBalancer:
      simple: RANDOM
  subsets:
  - name: v1
    labels:
      version: v10
  - name: v2
    labels:
      notfoundlabel: v2
  - name: v3
    labels:
      version: v3

2.4. MeshPolicy enabling mTLS is missing

Istio has the ability to define mTLS communications at mesh level. In order to do that, Istio needs one DestinationRule and one MeshPolicy. The DestinationRule configures all the clients of the mesh to use mTLS protocol on their connections. The MeshPolicy defines what authentication methods can be accepted on the workload of the whole mesh. If the MeshPolicy is not found or doesn’t exist and the mesh-wide DestinationRule is on ISTIO_MUTUAL mode, all the communication returns 500 errors.

Resolution

Add a MeshPolicy named as default without specifying targets but setting peers mtls mode to STRICT or PERMISSIVE. The MeshPolicy should be like this.

Severity

Error

Example

apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "default"
  namespace: "istio-system"
spec:
  host: "*.local"
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL

2.5. mTLS settings of a non-local Destination Rule are overridden

Istio allows you to define DestinationRule at three different levels: mesh, namespace and service level. A mesh may have multiple DRs. In case of having two DestinationRules on the first one is at a lower level than the second one, the first one overrides the TLS values of the second one.

Resolution

This validation aims to warn Kiali users that they may be disabling/enabling mTLS from the higher DestinationRule. Merging the TLS settings to one of the DestinationRules is the only way to fix this validation. However, this is a valid scenario so it might be impossible to remove this warning.

Severity

Warning

Example

apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "default"
  namespace: "istio-system"
spec:
  host: "*.local"
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
  name: reviews
spec:
  host: reviews
  trafficPolicy:
    loadBalancer:
      simple: RANDOM
  subsets:
  - name: v1
    labels:
      version: v10
  - name: v2
    labels:
      version: v2
  - name: v3
    labels:
      version: v3

2.6. Policy enabling namespace-wide mTLS is missing

Istio has the ability to define mTLS communications at namespace level. In order to do that, Istio needs both a DestinationRule and a Policy targeting all the clients/workloads of the specific namespace. The policy allows mTLS authentication method for all the workloads within a namespace. The DestinationRule defines all the clients within the namespace to start communications in mTLS mode. If the Policy is not found and the DestinationRule is on STRICT mode in that namespace, all the communications within that namespace returns 500 errors.

Resolution

A Policy enabling mTLS method is needed for the workloads in the namespace. Otherwise all the clients start mTLS connections that those workloads won’t be ready to manage. Add a Policy named as default without specifying targets but setting peers mTLS mode to STRICT or PERMISSIVE in the same namespace as the DestinationRule.

Severity

Error

Example

apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "enable-mtls"
  namespace: "bookinfo"
spec:
  host: "*.bookinfo.svc.cluster.local"
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL

2.7. Policy with TLS strict mode found, it should be permissive

Istio needs both a DestinationRule and Policy to enable mTLS communications. The policy configures the authentication method accepted for all the targeted workloads. The DestinationRule defines which is the authentication method that the clients of specific workloads has to start communications with.

Resolution

Kiali has found that there is a DestinationRule sending traffic without mTLS authentication method. There are two different ways to fix this situation. You can either change the Policy applying to PERMISSIVE mode or change the DestinationRule to start communications using mTLS.

Severity

Error

Example

apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "disable-mtls"
  namespace: "bookinfo"
spec:
  host: "*.bookinfo.svc.cluster.local"
  trafficPolicy:
    tls:
      mode: DISABLE
---
apiVersion: "authentication.istio.io/v1alpha1"
kind: "Policy"
metadata:
  name: "default"
  namespace: "bookinfo"
spec:
  peers:
  - mtls:
      mode: STRICT

2.8. MeshPolicy enabling mTLS found, permissive policy is needed

Istio needs both a DestinationRule and Policy to enable mTLS communications. The policy configures the authentication method accepted for all the targeted workloads. The DestinationRule defines which is the authentication method that the clients of specific workloads has to start communications with.

Kiali found a DestinationRule starting communications without TLS but there was a MeshPolicy allowing services to accept only requests in mTLS.

Resolution

There are two ways to fix this situation. You can either change the MeshPolicy to enable PERMISSIVE mode to all the workloads in the mesh or change the DestinatonRule to enable mTLS instead of disabling it (change the mode to ISTIO_MUTUAL).

Severity

Error

Example

apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "default"
  namespace: "bookinfo"
spec:
  host: "*.bookinfo.svc.cluster.local"
  trafficPolicy:
    tls:
      mode: DISABLE
---
apiVersion: "authentication.istio.io/v1alpha1"
kind: "MeshPolicy"
metadata:
  name: "default"
spec:
  peers:
  - mtls:
      mode: STRICT

3. VirtualServices

3.1. DestinationWeight on route doesn’t have a valid service (host not found)

VirtualService routes matching requests to a service inside your mesh. Routing can also match a subset of traffic to a certain version of it for example. Any service inside the mesh must be targeted by its name, the IP address are only allowed for hosts defined through a Gateway. Host must be in a short name or FQDN format. Short name will evaluate to VS' namespace, regardless of where the actual service might be placed.

If the host is not found, Istio ignores the defined rules. However, if a subset with a Destination Rule is not found it affects all the subsets and all the routings. As such, care must be taken that the Destination rule is available before deploying the Virtual Service.

Resolution

Correct the host to point to a correct service (in this namespace or with FQDN to other namespaces), deploy the missing service to the mesh or remove the configuration linking to that non-existing service.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details
  http:
  - route:
    - destination:
        host: nonexistentsvc
        subset: v2

3.2. VirtualService is pointing to a non-existent gateway

By default, VirtualService routes apply to sidecars inside the mesh. The gateway field allows to override that default and if anything is defined, the VS applies to those selected. 'mesh' is a reserved gateway name and means all the sidecars in the mesh. If one wishes to apply the VS to gateways as well as the sidecars, the 'mesh' keyword must be used as one of the gateways. Incorrect gateways mean that the VS is not applied correctly.

Resolution

Fix the possible gateway field to target all necessary gateways or remove the field if the default 'mesh' is enough.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details
  gateways:
  - bookinfo-gateway
  http:
  - route:
    - destination:
        host: details
        subset: v2

3.3. Subset not found

VirtualService routes matching requests to a service inside your mesh. Routing can also match a subset of traffic to a certain version of it for example. The subsets referred in a VirtualService have to be defined in one DestinationRule.

If one route in the VirtualService points to a subset that doesn’t exist Istio won’t be able to send traffic to a service.

Resolution

Fix the routes that points to a non existing subsets. It might be fixing a typo in the subset’s name or defining the missing subset in a DestinationRule.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: nosubset
      weight: 90
    - destination:
        host: reviews
        subset: v2
      weight: 10

See Also

3.4. VirtualService doesn’t define any route protocol

VirtualService is a defined set of rules for routing certain type of traffic to target destinations with rules. At least one, 'tcp', 'http' or 'tls' must be defined.

Resolution

This appears to be a configuration error. Fix the definition.

Severity

Error

Example

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: details
spec:
  hosts:
  - details

3.5. More than one Virtual Service for same host

A VirtualService defines a set of traffic routing rules to apply when a host is addressed. Each routing rule defines matching criteria for traffic of a specific protocol. If the traffic is matched, then it is sent to a named destination service (or subset/version of it) defined in the registry.

Resolution

This is valid configuration only if VirtualService is bound to a gateway, sidecars do not accept this behavior. There are several caveats when using this method and defining the same parts in multiple Virtual Service definitions is not recommended. While Istio will merge the configuration, it does not guarantee any ordering for cross-resource merging and only the first seen configuration is applied (rest ignored). As recommended, each VS definition should have a 'catch-all' situation, but this can only be defined in a definition affecting the same host.

Severity

Warning

Example

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews
spec:
  hosts:
    - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 90
    - destination:
        host: reviews
        subset: v2
      weight: 10
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: reviews-cp
spec:
  hosts:
    - reviews
  http:
  - route:
    - destination:
        host: reviews
        subset: v1
      weight: 90
    - destination:
        host: reviews
        subset: v2
      weight: 10

4. Services

4.1. Port name must follow <protocol>[-suffix] form

Istio requires the service ports to follow the naming form of 'protocol-suffix' where the '-suffix' part is optional. If the naming does not match this form (or is undefined), Istio treats all the traffic TCP instead of the defined protocol in the definition. Dash is a required character between protocol and suffix. For example, 'http2foo' is not valid, while 'http2-foo' is (for http2 protocol).

Resolution

Rename the service port name field to follow the form and the traffic flows correctly.

Severity

Error

Example

apiVersion: v1
kind: Service
metadata:
  name: ratings-java-svc
  namespace: bookinfo
  labels:
    app: ratings
    service: ratings-svc
spec:
  ports:
  - port: 9080
    name: wrong-http
  selector:
    app: ratings-java
    version: v1

4.2. Service port and deployment port do not match

Service definition has a combination of labels and port definitions that are not matching to any workloads. This means the deployment will be unsuccessful and no traffic can flow between these two resources. The port is read from the Service 'TargetPort' definition first and if undefined, the 'Port' field is used as Kubernetes defaults the 'TargetPort' to 'Port'. If the 'TargetPort' is using a integer, the port numbers are compared and if the 'TargetPort' is a string, the deployment’s portName is used for comparison.

Resolution

Fix the port definitions in the workload or in the service definition to ensure they match.

Severity

Error

Example

Invalid example with port definitions unmatched:

apiVersion: v1
kind: Service
metadata:
  name: ratings-java-svc
  namespace: ratings-java
  labels:
    app: ratings
    service: ratings-svc
spec:
  ports:
  - port: 9080
    name: http
  selector:
    app: ratings-java
    version: v1
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: ratings-java
  namespace: ratings-java
  labels:
    app: ratings-java
    version: v1
spec:
  replicas: 1
  template:
    metadata:
      annotations:
         sidecar.istio.io/inject: "true"
      labels:
        app: ratings-java
        version: v1
    spec:
      containers:
      - name: ratings-java
        image: pilhuhn/ratings-java:f
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080

Valid example using targetPort definition matching:

apiVersion: v1
kind: Service
metadata:
  name: ratings-java-svc
  namespace: ratings-java
  labels:
    app: ratings
    service: ratings-svc
spec:
  ports:
  - port: 9080
    targetPort: 8080
    name: http
  selector:
    app: ratings-java
    version: v1
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: ratings-java
  namespace: ratings-java
  labels:
    app: ratings-java
    version: v1
spec:
  replicas: 1
  template:
    metadata:
      annotations:
         sidecar.istio.io/inject: "true"
      labels:
        app: ratings-java
        version: v1
    spec:
      containers:
      - name: ratings-java
        image: pilhuhn/ratings-java:f
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080

5. Mesh Policies

5.1. Mesh-wide Destination Rule enabling mTLS is missing

Istio has the ability to define mTLS communications at mesh level. In order to do that, Istio needs one DestinationRule and one MeshPolicy. The DestinationRule configures all the clients of the mesh to use mTLS protocol on their connections. The MeshPolicy defines what authentication methods can be accepted on the workload of the whole mesh. If the DestinationRule is not found or doesn’t exist and the MeshPolicy is on STRICT mode, all the communication returns 500 errors.

Resolution

Add a DestinationRule named as default with "*.cluster" host and ISTIO_MUTUAL as tls trafficPolicy mode. The DestinationRule should be like this.

Severity

Error

Example

# Make sure there isn't any DestinationRule enabling meshwide mTLS
apiVersion: "authentication.istio.io/v1alpha1"
kind: "MeshPolicy"
metadata:
  name: "default"
spec:
  peers:
  - mtls: {}

6. ServiceRoles and ServiceRoleBindings

6.1. Unable to find all the defined services

Services can be listed with an exact match, prefix match as well as suffix match. Using "*" refers to all the services in this namespace. This error indicates the services list is pointing to a service that can not be found from this namespace.

Resolution

Deploy the missing services or fix the services list to point to correct services.

Severity

Error

Example

apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRole
metadata:
  name: details-reviews-viewer
  namespace: bookinfo
spec:
  rules:
  - services: ["wrongservice.bookinfo.svc.cluster.local", "reviews.bookinfo.svc.cluster.local"]
    methods: ["GET"]
    constraints:
      - key: "destination.labels[version]"
        values: ["v1"]

6.2. ServiceRole can only point to current namespace

Services can be listed with an exact match, prefix match as well as suffix match. Using "*" refers to all the services in this namespace. Although FQDN can be used, the namespace of the services must be the same as ServiceRole’s deployment.

Resolution

If the services in question are located in another namespace, deploy this ServiceRole to that namespace, or deploy the services to this namespace.

Severity

Error

Example

apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRole
metadata:
  name: details-reviews-viewer
  namespace: bookinfo
spec:
  rules:
  - services: ["details.test.svc.cluster.local", "reviews.bookinfo.svc.cluster.local"]
    methods: ["GET"]
    constraints:
      - key: "destination.labels[version]"
        values: ["v1"]

6.3. ServiceRole does not exists in this namespace

ServiceRoleBinding assigns a ServiceRole to subjects. As such, it must refer to a ServiceRole object and this object can only reside in the same namespace. Cross-namespace refers are not valid.

Resolution

Deploy the missing ServiceRole to the same namespace.

Severity

Error

Example

apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRole
metadata:
  name: details-reviews-viewer
  namespace: default
spec:
  rules:
  - services: ["details.bookinfo.svc.cluster.local", "reviews.bookinfo.svc.cluster.local"]
    methods: ["GET"]
    constraints:
      - key: "destination.labels[version]"
        values: ["v1"]
---
apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRoleBinding
metadata:
  name: bind-details-reviews
  namespace: bookinfo
spec:
  subjects:
  - user: "cluster.local/ns/bookinfo/sa/bookinfo-productpage"
  roleRef:
    kind: ServiceRole
    name: "details-reviews-viewer"

7. Unknown

7.1. Unable to verify the validity, cross-namespace validation is not supported for this field

In certain cases, Kiali is unable to validate the field since it spans another namespace to which the validator is not capable of looking at. In such cases, Kiali will mark this field with a grey icon indicating that the fields correctness could not be verified. This does not necessarily mean there is an error, but that the user should be careful and do the validation manually.